MINOR: [C#] Bump xunit from 2.9.2 to 2.9.3 in /csharp (#45243)

Bumps [xunit](https://github.com/xunit/xunit) from 2.9.2 to 2.9.3.
<details>
<summary>Commits</summary>
<ul>
<li><a href="https://github.com/xunit/xunit/commit/9712244020d385955d33136b3fe3e87de43539cd"><code>9712244</code></a> v2.9.3</li>
<li><a href="https://github.com/xunit/xunit/commit/dbba909f1b7922a4d254c9d064a8f1458d996325"><code>dbba909</code></a> <a href="https://redirect.github.com/xunit/xunit/issues/3088">#3088</a>: Assert.Equivalent throws NotSupportedException for types with getters ...</li>
<li><a href="https://github.com/xunit/xunit/commit/cdf2114812a6312c4c0b1ca182a1fe6a65692422"><code>cdf2114</code></a> Stick to .NET SDK 8</li>
<li><a href="https://github.com/xunit/xunit/commit/5716c89078aa82bdd11892cdcc1b1b66cbcbb9b5"><code>5716c89</code></a> Disable NETSDK1215 and NU1902 for .NET 9 SDK</li>
<li><a href="https://github.com/xunit/xunit/commit/607007022f26cf524a7e7b350ed8f1b08b73796b"><code>6070070</code></a> TeamCity Reporter. Remove flow id from name of test suites. (<a href="https://redirect.github.com/xunit/xunit/issues/3054">#3054</a>)</li>
<li><a href="https://github.com/xunit/xunit/commit/bfd42e0ed5c7fc177e871a438da6cd27fe09a2ed"><code>bfd42e0</code></a> <a href="https://redirect.github.com/xunit/xunit/issues/3053">#3053</a>: Class data derived from TheoryData&lt;SomeType[]&gt; is broken</li>
<li><a href="https://github.com/xunit/xunit/commit/5f7494f7fdfe3e1307e9ce5b84acb64abacb0df7"><code>5f7494f</code></a> Update assertions and tests</li>
<li><a href="https://github.com/xunit/xunit/commit/3f9460dec39560e97e97d708fc98377f3bff53eb"><code>3f9460d</code></a> Updated README</li>
<li><a href="https://github.com/xunit/xunit/commit/d1206d9a6a922e1aaceb1f6587548461b06c318d"><code>d1206d9</code></a> Update README</li>
<li><a href="https://github.com/xunit/xunit/commit/dc5dd04ac3dce21b647044972198e399bcbd152c"><code>dc5dd04</code></a> Bump up to v2.9.3-pre</li>
<li>See full diff in <a href="https://github.com/xunit/xunit/compare/v2-2.9.2...v2-2.9.3">compare view</a></li>
</ul>
</details>
<br />

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Lead-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Curt Hagenlocher <[email protected]>
Signed-off-by: Curt Hagenlocher <[email protected]>

Author: dependabot[bot]

csharp/test/Apache.Arrow.Compression.Tests/Apache.Arrow.Compression.Tests.csproj

@@ -8,7 +8,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.0.1" />
   </ItemGroup>
 

csharp/test/Apache.Arrow.Flight.Sql.Tests/Apache.Arrow.Flight.Sql.Tests.csproj

@@ -7,7 +7,7 @@
 
     <ItemGroup>
       <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-      <PackageReference Include="xunit" Version="2.9.2" />
+      <PackageReference Include="xunit" Version="2.9.3" />
       <PackageReference Include="xunit.runner.visualstudio" Version="3.0.1" />
       <PackageReference Include="coverlet.collector" Version="6.0.3" />
     </ItemGroup>

csharp/test/Apache.Arrow.Flight.Tests/Apache.Arrow.Flight.Tests.csproj

@@ -7,7 +7,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.runner.visualstudio" Version="3.0.1" />
     <PackageReference Include="coverlet.collector" Version="6.0.3" />
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csharp/test/Apache.Arrow.Tests/Apache.Arrow.Tests.csproj

@@ -30,7 +30,7 @@
 
   <ItemGroup>
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.12.0" />
-    <PackageReference Include="xunit" Version="2.9.2" />
+    <PackageReference Include="xunit" Version="2.9.3" />
     <PackageReference Include="xunit.skippablefact" Version="1.5.23" />
     <PackageReference Include="pythonnet" Version="3.0.5" />
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